If people who have been treated for bowel cancer replace regular sodas - which have been sweetened with sugars - with low-calorie diet sodas, their chances of survival increase and the chance of disease recurrence decreases. A group of American researchers report this in PLoS One.

Study
The researchers used data collected in the first decade of the 21st century in the CALGB 89803 study. In that project scientist compared the effect of two different chemotherapy with each other. The 1018 subjects had colon cancer, and were in stage 3. At that stage, the cancer has spread to the immediate environment from where it originated, but has not yet spread through the body.

In the CALGB 89803 study data on lifestyle of the participants were also recorded.

Results
The more often the study participants drank light-soda, the smaller the chance of their disease returning and the less likely they are to die. In the group with the highest intake, the risk of both recurrence of the disease and mortality was about halved compared to the group that never drank diet sodas.

When the researchers started to puzzle, they discovered that the effect was not caused by diet sodas having a positive effect on the health of the study participants. The effect was caused by the fact that the study participants drank less sodas with sugars as they drank more diet sodas.

So - the study has not shown that light-soda is healthy. It showed that sugar and high-fructose corn syrup in soft drinks is unhealthy.

That discovery did not come as a bolt out of the blue. In another epidemiological study, which was published in 2014, the researchers had already discovered that the consumption of sugared sodas reduces the chances of survival of colorectal cancer patients. [PLoS One. 2014 Jun 17;9(6):e99816.] A healthy body weight and a lifestyle with a lot of exercise could reduce the harmful effect of regular soft drinks.

That research was based on data from the CALGB 89803 study as well.

Conclusion

"Artificially sweetened drinks have a checkered reputation in the public because of purported health risks that have never really been documented", says research leader Charles Fuchs from Yale Cancer Center in a press release. [sciencedaily.com July 19, 2018] "Our study clearly shows they help avoid cancer recurrence and death in patients who have been treated for advanced colon cancer, and that is an exciting finding."

"In sum, this prospective study of patients with stage III colon cancer, embedded in a randomized clinical trial, suggests improved patient outcome with increased consumption of artificially sweetened beverage, which may be accounted for, completely or in part, by substitution for sugar-sweetened alternatives", write the researchers.

"Although our study cannot offer evidence for causality given its observational design, our findings offer further insight into the role of diet and lifestyle in colon cancer outcomes and potentially meaningful recommendations for clinical care."